Switching device for underwater turbine

ABSTRACT

A hydromechanical device arranged to be provided in a streaming water for generating power. A first inlet conduit is arranged to convey a first flow of water. A second inlet conduit is arranged to convey a second flow of water. A switching device is provided immediately downstream the inlet conduits. A turbine is provided downstream the switching device. The switching device is arranged to convey in an alternating order, the first flow and the second flow to the turbine in such a way that the first flow and the second flow alternately drives the turbine.

BACKGROUND OF THE INVENTION AND PRIOR ART

The present invention refers to a hydromechanical device arranged to be provided in a streaming water for generating power according to the preamble of claims 1.

JP-56060866 discloses a water power plant comprising a pipe and a turbine provided at the downstream end of the pipe. At the upstream end there is a funnel-like member for increasing the speed of the flow.

JP-2004068641 discloses a water turbine plant comprising several successive turbines.

EP-38321 discloses a water power plant having an inlet pipe that is divided into two or more part pipes. The part pipes converge towards a common turbine.

WO94/20751 discloses a water power plant having two parallel pipes. The pipes are arranged to be alternately shut off in order to create a hydraulic shock in the water in the respective pipe.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an improved hydromechanical device adapted for generating power. Especially, it is aimed at a hydromechanical device which can be used for generating power when the streaming water has a relatively low flow velocity.

This object is achieved by means of the hydromechanical device initially defined which is characterized in that the switching device is arranged to convey in an alternating order, the first flow and the second flow to the turbine in such a way that the first flow and the second flow alternately drives the turbine. By means of such a switching device the flow with the highest kinetic energy can be used to operate the turbine. In such a way the turbine may in every moment be operated by the flow of the inlet conduit where the water has the highest kinetic energy.

According to an embodiment of the invention, the switching device is arranged to convey the second flow out of the hydromechanical device when the first flow is conveyed to the turbine, and to convey the first flow out of the hydromechanical device when the second flow is conveyed to the turbine. In such a way the flow which is conveyed out of the hydromechanical device will during this time period accelerate and obtain a higher kinetic energy, whereas the flow conveyed to the turbine will decrease its velocity. By means of the switching device it is possible to switch from the flow with a relatively low velocity to the flow with a relatively high velocity and in such a manner increase the efficiency of the turbine in comparison with a turbine driven only by a single flow of water. The switching device may then be arranged to convey the flow that is conveyed out of the hydromechanical device directly back to the streaming water.

According to a further embodiment of the invention, the switching device comprises at least a first turbine passage from the first inlet conduit to the turbine, at least a second turbine passage from the second inlet conduit to the turbine, and a valve device, which is arranged to alternately take a first position and a second position, wherein the valve device in the first position maintains the first turbine passage open and the second turbine passage closed, and in the second position maintains the first turbine passage closed and the second turbine passage open. Each of the passages may have an upstream orifice arranged in a common plane, wherein the valve device comprises a valve member movable in parallel to the common plane between the first position and the second position. In such a way a valve device having a valve member reciprocating between two positions may be achieved in a relatively easy manner.

According to a further embodiment of the invention, the switching device also comprises at least a first outlet passage from the first inlet conduit out of the hydromechanical device, at least a second outlet passage from the second inlet conduit out of the hydromechanical device, wherein the valve device in the first position maintains the first turbine passage and the second outlet passage open and the first outlet passage and the second turbine passage closed, and in the second position maintains the first turbine passage and the second outlet passage closed and the first outlet passage and the second turbine passage open.

According to a further embodiment of the invention, each of the passages have an upstream orifice arranged in a common plane, wherein the valve device comprises a valve member movable in parallel to the common plane between the first position and the second position The orifices may be arranged along a circular path, wherein the valve member is movable along the circular path. Furthermore, the valve device may comprise a motor member adapted to operate the valve member. Especially, the motor member may be adapted to rotate the valve member.

According to a further embodiment of the invention, the switching device comprises a rotary part connected to a turbine inlet conduit, which is rotatable around an axis together with the rotary part to be aligned with one of the inlet conduits and has a downstream end connected to the turbine.

According to a further embodiment of the invention, the first inlet conduit and the second inlet conduit have a first transition conduit and a second transition conduit, respectively, provided immediately upstream the switching device.

According to a further embodiment of the invention, the inlet conduits extend substantially in parallel to each other. Preferably, the conduits are arranged relatively close to each other.

According to a further embodiment of the invention, the hydromechanical device comprises an inlet member adapted to introduce water into the inlet conduits. The inlet member may have a decreasing flow area in the direction of the flow and thus collect a large quantity of water which is conveyed into the inlet conduits. Preferably, the inlet conduits have a respective upstream end and a respective downstream end at the switching device, wherein the inlet member is provided at the upstream ends of the inlet conduits.

According to a further embodiment of the invention, the hydromechanical device comprises at least one intermediate member arranged downstream the upstream end for introducing additional water into the inlet conduit. Thereby, the device may comprise a first inlet valve member for opening and closing a passage into the first inlet conduit from the intermediate member and a second inlet valve ^(member) for opening and closing a passage into the second inlet conduit from the intermediate member. Preferably, the first inlet valve member is arranged to open the passage when the first turbine passage is closed and the first outlet passage is open. The second inlet valve member is preferably open when the second turbine passage is closed and the second outlet passage is open.

According to a further embodiment of the invention, the opening of the valve members is facilitated by means of respective first and second spring members. Furthermore, the closing of the valve members may be facilitated by means of a pressure difference of the water flowing through the respective inlet conduit at a position upstream the intermediate member and a position downstream the intermediate member.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is now to be explained more closely by a description of various embodiments and with reference to the drawings attached hereto.

FIG. 1 illustrates schematically a hydromechanical device according to an embodiment of the invention with a valve device in a first position.

FIG. 2 illustrates schematically the hydromechanical device in FIG. 1 with the valve device in a second position.

FIG. 3 discloses schematically a side view of a switching device of the device in FIG. 1.

FIG. 4 discloses a sectional view along the lines A-A in FIG. 3.

FIG. 5 discloses a sectional view along the lone B-B in FIG. 3.

FIG. 6 discloses a sectional view through a valve member along the line C-C in FIG. 3.

FIG. 7 discloses a side view along the line D-D in FIG. 6.

FIG. 8 discloses schematically a view from above of a part of a first inlet conduit and a second inlet conduit of the hydromechanical device in FIG. 1.

FIG. 9 discloses schematically a side view of an intermediate valve station according to a further embodiment.

FIG. 10 discloses schematically a downstream view of a switching device according to a further embodiment.

FIG. 11 discloses schematically a cross-sectional view of the switching device along the line XI-XI in FIG. 10.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS OF THE INVENTION

FIGS. 1 and 2 discloses schematically a hydromechanical device according to the invention. The hydromechanical device is arranged to be provided in a streaming water for generating power. The streaming water w can be any kind of water stream, for instance a river, a water channel, a lake etc. The hydromechanical device is adapted to be arranged in a streaming water w and to absorb the energy of a streaming water with various flow velocities.

The hydromechanical device comprises a first inlet conduit 1, which is arranged to convey a first flow of water, and a second inlet conduit 2, which is arranged to convey a second flow of water. The first inlet conduit 1 and the second inlet conduit 2 have a downstream end and a upstream end with respect to the flow direction f and extend in parallel, or substantially in parallel, to each other. Furthermore, the first inlet conduit and the second inlet conduit 2 extend approximately in parallel to the flow direction f of the streaming water w, i.e. the first flow, the second flow and the streaming water w flow in substantially the same flow direction f. Preferably, the first inlet conduit 1 and the second inlet conduit 2 are arranged relatively close to each other, for instance with a distance between the first inlet conduit 1 and the second conduit 2 which is smaller than the diameter d of the inlet conduits 1, 2, see FIG. 8. The diameter d may for instance be about 0.2, 0.4, 0.6, 1 m or more. The first inlet conduit 1 and the second inlet conduit 2 have the same, or substantially the same, diameter and length. The lengths of the conduits 1 and 2 can vary but is preferably long, for instance 10, 50, 100, 150, 200, 300, 400, 500, 600, 800, 1 000 m or more. Moreover, the length of the conduits 1, 2 may, for instance, be approximately 5 times the diameter of the conduits 1, 2.

Furthermore, the hydromechanical device comprises a switching device 3, which is provided in the proximity of the downstream end of the inlet conduits 1, 2, and a turbine 4, which is provided downstream the switching device 3. The turbine 4 can be a rotary machine of any suitable kind for converting the kinetic energy of the water into a rotating mechanical energy. The turbine 4 has a output shaft 5 which is connected to or forms an input shaft of an electrical generator 6 for converting the rotary energy of the turbine 4 into electric energy. The turbine 4 may be connected to or include a flywheel 4′ in order to achieve a stable rotation of the turbine 4.

The switching device 3 is arranged to convey, in an alternating order, the first flow from the first inlet conduit 1 and the second flow of the second inlet conduit 2 to the turbine 4 in such a way that the first flow and the second flow alternately drives the turbine 4. Furthermore, the switching device 3 is arranged to convey the second flow of the second inlet conduit 2 out of the hydromechanical device when the first flow is conveyed to the turbine 4, and to convey the first flow of the first inlet conduit 1 out of the hydromechanical device when the second flow is conveyed to the turbine 4. More specifically, the switching device 3 is arranged to convey the flow that is conveyed out of the hydromechanical device directly back to the streaming water w. Consequently, at every moment of time one of the first and the second flows will be conveyed through the turbine 4 and the other of the first and second flows will be conveyed back to the streaming water w. One of the first and second flows will thus be conveyed through the turbine 4 during a time period during which the other of the first and second flows will be conveyed back to the streaming water w. The switching device 3 is preferably adapted to permit or perform adjustment of the length of the time period. For instance, the time period could be in the order of a few seconds. During each such time period the flow being conveyed back to the streaming water w will be accelerated, whereas the water being conveyed to the turbine 4 will be retarded.

The switching device 3, schematically illustrated in FIGS. 1 and 2, comprises a first turbine passage 11 extending from the first inlet conduit 1 to the turbine 4, a second turbine passage 12 extending from the second inlet conduit 2 to the turbine 4, a first outlet passage 21 extending from the first inlet conduit 1 out of the hydromechanical device, and a second outlet passage 22 extending from the second inlet conduit 2 out of the hydromechanical device.

Furthermore, the switching device 3 comprises a valve device 15. In FIGS. 1 and 2, the valve device 15 is illustrated by four valve members 11′, 12′, 21′ and 22′. The valve device 15 is arranged to alternately take a first position and a second position. The first position is illustrated in FIG. 1, whereas the second position is illustrated in FIG. 2. In the first position, the valve device 15 maintains the first turbine passage 11 open, the second turbine passage 12 closed, the first outlet passage 21 closed and the second outlet passage 22 open. Consequently, in the first position the first flow from the first inlet conduit 1 is conveyed through the first turbine passage 11 to the turbine 4, whereas the second flow of the second inlet conduit 2 is conveyed out of the hydromechanical device back to the streaming water w. In the second position, the valve device 15 maintains the first turbine passage 11 closed, the second turbine passage 12 open, the first outlet passage 21 open and the second outlet passage 22 closed. Consequently, in the second position the second flow of the second inlet conduit 2 will be conveyed through the second turbine passage 12 to the turbine 4, whereas the first flow of the first inlet conduit 1 will be conveyed out of the hydromechanical device back to the streaming water w.

The valve device 15 and the valve members 11′, 12′, 21′, 22′ disclosed in FIGS. 1 and 2 can be of any suitable kind, for instance disc valves. FIGS. 3-7 discloses a switching device 3 with a valve device 15 of another design which is shown as an example of a preferred embodiment. The switching device 3 has a longitudinal centre axis x being substantially parallel with the flow direction f, and comprises a housing 30 enclosing the switching device 3 and the valve device 15 proper. The housing 30 also encloses a downstream end portion of the first inlet conduit 1 and the second inlet conduit 2. The housing 30 is divided into a first part 31 and a second part 32 by means of a partitioning wall 33.

Each of the turbine passages 11, 12 and the outlet passages 21, 22 has an upstream orifice illustrated in FIG. 4. The upstream orifices are arranged in a common plane substantially perpendicular to the flow direction. As can be seen from FIGS. 4 and 5 the switching device 3 comprises a plurality of first turbine passages 11, first outlet passages 21, second turbine passages 12 and second outlet passages 22. The valve device 15 comprises a valve member 35 which is movable in parallel to the common plane of the orifices. The valve device 15 also comprises a motor member 36 adapted to operate the valve member 35. The motor member 36 is adapted to rotate the valve member 35 around the longitudinal axis x with a reciprocating movement. The valve member 35 is designed as a disc comprising alternately located passages 37 and wall elements 38.

The above mentioned downstream end portion of the first inlet conduit 1 and the second inlet conduit 2 forms a first transition conduit 41 of the first inlet conduit 1, and a second transition conduit 42 of the second inlet conduit 2. The first transition conduit 41 and the second transition conduit 42 are thus provided immediately upstream the switching device 3 and more specifically immediately upstream the valve member 35. The transition conduits 41 and 42 are formed by a first frustoconical member 33 being concentric to the longitudinal centre axis x, and by wedge like members 44 arranged on the valve member 35 and tapering in a direction opposite to the flow direction f from the upstream side wall of the valve member 35.

Downstream the valve member 35 and the above mentioned orifices, the housing 30 has a tapering diameter in the flow direction f. The outlet passages 21 and 22 are defined by a bottom wall 47 being substantially parallel to the centre axis x.

As can be seen from FIG. 1 the first inlet conduit 1 and the second inlet conduit 2 have an inlet member 50 provided at the upstream end of the inlet conduits 1 and 2. In the embodiment disclosed, the inlet member 50 has the shape of a funnel 50 having a tapering flow area in the flow direction f and thus adapted to convey a quantity of water to be introduced into the inlet conduits 1 and 2. Furthermore, the hydromechanical device may comprise one, two, three, four or more intermediate members 51 in the form of funnels arranged downstream the upstream ends of the inlet conduits 1, 2 for introducing water into the first inlet conduit 1 and the second inlet conduit 2. The member 50 and/or the intermediate member 51 may be adjustable, i.e. the degree of the tapering flow area may be adjusted. In the embodiments disclosed, the members 50, 51 comprise funnels tapering with an angle α to the flow direction f, wherein the angle α may be adjusted by any suitable adjustment member (not disclosed).

Furthermore, the hydromechanical device comprises a first inlet valve member 61 for opening and closing a passage into the first inlet conduit 1 from the intermediate member 51, and a second inlet valve member 62 for opening and closing a passage into the second inlet conduit 2 from the intermediate member 51, see FIG. 8. Such valve members 61, 62 can be provided in each intermediate member 51. The opening of the valve members 61, 62 is facilitated by means of a respective first and second spring members 71, 72. The closing of the valve members 61, 62 is facilitated by means of a pressure difference of the water flowing through the respective conduit 1, 2 at a position upstream the intermediate member 51 and downstream the intermediate member 51. The pressure of the water flowing through the respective conduit 1, 2 is transferred to a cylinder member 81, 82 in which a piston 83, 84 responds to the pressure difference and actuates the valve members 61, 62. The spring members 71, 72 are provided in the cylinders for acting on the piston 83, 84. Preferably, the operation of the valve members 61, 62 is associated with the operation of the valve device 15 in such a way that the valve member 61 of the first inlet conduit 1 is closed when the first turbine passage 11 is open, and the valve member 62 of the second inlet conduit 2 is closed when the turbine passage 12 is open. Furthermore, the valve member 61 is open when the outlet passage 21 is open and the valve member 62 is open when the outlet passage 22 is open.

FIG. 9 discloses an intermediate member 90 according to a further embodiment. The intermediate member 90 is mounted to one or all of the inlet conduits, in the embodiment disclosed to the first inlet conduit 1. The intermediate member 90 is provided at the upstream end of the first inlet conduit 1. The intermediate member 90 is connected to a upstream conduit 1′ extending through the intermediate member 90. The intermediate member 90 comprises a first valve element 91 and a second valve element 92, which are synchronised with the operation of the switching device 3. In FIG. 9, the first valve element 91 is open and the second valve element 92 is closed. The water flowing through the upstream conduit 1′ will thus pass through the intermediate member 90 back to the streaming water. The valve elements 91 and 92 are in the disclosed position, when the valve member 21′ is open, i.e. when the water in the first inlet conduit 1 is not conveyed to the turbine 4. When the valve member 21′ is closed and the valve member 11′ is open, i.e. when the streaming water is conveyed to the turbine 4, the first valve element 91 is closed and the second valve element 92 is open. The water flowing through the upstream conduit 1′ will then be conveyed to the first inlet conduit 1, which will contribute to the recover of the velocity of the water to the turbine 4.

FIGS. 10 and 11 disclose a further embodiment, which comprises four inlet conduits 101, 102, 103 and 104. The switching device 3 has a configuration differing from configuration of the switching device 3 in FIGS. 3-7. The switching device 3 comprises a stationary part 105 and a rotary part 106, which is rotatable by means of a motor member (not disclosed). Each of the inlet conduits 101-104 is connected to the stationary part 105 and extends through the stationary part 105. The rotary part 106 comprises or is connected to a turbine inlet conduit 115, which is rotatable around the longitudinal axis x together with the rotary part 106 to be aligned with one of the inlet conduits 101-104, i.e. an upstream end of the turbine inlet conduit 115 can be brought into alignment with one of the inlet conduits 101-10A. The turbine inlet conduit 115 has a downstream end that is connected to the turbine 4. The rotary part 106 has a configuration which supports the turbine inlet conduit 115 in alignment with one of the inlet conduits 101-104 and at the same time leaves the remaining inlet conduits 101-104 open so that the water flowing therethrough may flow back to the streaming water. Consequently, in the position disclosed in FIGS. 10 and 11, the first inlet conduit 101 is connected to the turbine 4 via the turbine inlet conduit 115, whereas the inlet conduits 102-103 lead back to the streaming water. When the velocity of the water flowing through the first conduit 101 has been reduced to a determined value, the rotary part 106 is rotated an angle distance so that the second inlet conduit 102 will be aligned with the turbine inlet conduit 115 and thus conveyed to the turbine 4. The rotary part may be rotated to alternatively and successively connect the inlet conduits 101-104 to the first passage 111 and the transition conduit 115. It is to be noted that the switching device 3 disclosed in FIGS. 10 and 11 may be used with another number of inlet conduits, for example 2, 3, 5, 6 or more. The inlet conduits 101-105 may be configured as the inlet conduits previously described in this application.

The present invention is not limited to the embodiments disclosed but may be varied and modified within the scope of the following claims. 

1. A hydromechanical device arranged to be provided in a streaming water for generating power, the device comprising: at least a first inlet conduit, arranged to convey a first flow of water, a second inlet conduit, arranged to convey a second flow of water, a switching device, provided immediately downstream the inlet conduit, and a turbine, which is provided downstream the switching device, wherein the switching device is arranged to convey in an alternating order, the first flow and the second flow to the turbine in such a way that the first flow and the second flow alternately drives the turbine.
 2. The device according to claim 1, wherein the switching device is arranged to convey the second flow out of the device when the first flow is conveyed to the turbine, and to convey the first flow out of the hydromechanical device when the second flow is conveyed to the turbine.
 3. The device according to claim 1, wherein the switching device is arranged to convey the flow that is conveyed out of the hydromechanical device directly back to the streaming water.
 4. The device according to claim 1, wherein the switching device comprises at least a first turbine passage from the first inlet conduit to the turbine, at least a second turbine passage from the second inlet conduit to the turbine, and a valve device, which is arranged to alternately take a first position and a second position, wherein the valve device in the first position maintains the first turbine passage open and the second turbine passage closed, and in the second position maintains the first turbine passage closed and the second turbine passage open.
 5. The device according to claim 4, wherein each of the passages has an upstream orifice arranged in a common plane and wherein the valve device comprises a valve member movable in parallel to the common plane between the first position and the second position.
 6. The device according to claim 4, wherein the switching device also comprises at least a first outlet passage from the first inlet conduit out of the hydromechanical device, at least a second outlet passage from the second inlet conduit out of the hydromechanical device, wherein the valve device in the first position maintains the first turbine passage and the second outlet passage open and the first outlet passage and the second turbine passage closed, and in the second position maintains the first turbine passage and the second outlet passage closed and the first outlet passage and the second turbine passage open.
 7. The device according to claim 6, wherein each of the passages has an upstream orifice arranged in a common plane and wherein the valve device comprises a valve member movable in parallel to the common plane between the first position and the second position.
 8. The device according to claim 7, wherein the orifices are arranged along a circular path, wherein the valve member is movable along the circular path.
 9. The device according to claim 7, wherein the valve device comprises a motor member adapted to operate the valve member.
 10. The device according to claim 8, wherein the motor member is adapted to rotate the valve member.
 11. The device according to claim 1, wherein the switching device comprises a rotary part connected to a turbine inlet conduit, which is rotatable around an axis together with the rotary part to be aligned with one of the inlet conduits and has a downstream end connected to the turbine.
 12. The device according to claim 1, wherein the first inlet conduit and the second inlet conduit have a first transition conduit and a second transition conduit, respectively, provided immediately upstream the switching device.
 13. The device according to claim 1, wherein the inlet conduits extends extend substantially in parallel to each other.
 14. The device according to claim 1, wherein the hydromechanical device comprises an inlet member adapted to introduce water into the inlet conduits.
 15. The device according to claim 14, wherein the inlet conduits have a respective upstream end and a respective downstream end in the proximity of the switching device, wherein the inlet member is provided at the upstream end of the inlet conduits.
 16. The device according to claim 15, further comprising: at least one intermediate member arranged downstream the upstream end for introducing water from the streaming water into at least one of the inlet conduits.
 17. The device according to claim 16, further comprising: a first inlet valve member for opening and closing a passage into the first inlet conduit from the intermediate member, and a second inlet valve member for opening and closing a passage into the second inlet conduit from the intermediate member.
 18. The device according to claim 17, further comprising: first and second spring members configured to facilitate opening of the valve members.
 19. The device according to claim 17, wherein the closing of the valve members is facilitated by means of a pressure difference of the water flowing through the respective conduit at a position upstream the intermediate member and a position downstream the intermediate member. 